Automatic drain-valve



T. W. DEMAREST.

AUTOMATIC DRATN'VALVE.

APPLICATION HLED mp2s. 1917.

Ti W. DEMAREST.

AUTOMATIC DRAIN VALVE.

APPucATmN man MAR.23, 1917.

Patented June 15, 1920. 2 SHEETS--SHEET 2.

IN V EN TOR. mel/f2 BY M/ @www I ATTORNEY' WI TNESS THOMAS W. DEMAREST, OF FORT WAYNE, INDIANA.

AUTOMATIC DRAIN-VALVE,

Specification of Letters Patent. tPatente/(1 June 15, 192() Application led March 23, 1917. Serial No. 157,016.

To all whom t may concern.'

Be it known that I, THOMAS W. DEMAREsr, a citizen of the United States, and a resident of F ort Wayne, in the county of Allen and State of Indiana, have invented certain new and useful Improvements in Automatic Drain-Valves, of which the following is a specification.

My present invention relates to improvements in means for relieving containers or systems of excess of fluid and more particularly to means for draining. containers or systems of liquids and for relieving systems of any excess pressure which may be generated thereinV and has special reference to the provision of improved automatically acting containers or systems for relieving locomotive cylinders of water of condensation and excess pressure.

"ated rlhe principal objects of my present invention are the provision of improved means for draining liquid from cylinders and other cavities or receptacles subject to steam' or other fluid pressure, the provision of improved means for relieving excess pressure in cylinders or other: cavities or receptacles subject to fluid pressure, the provision of an improved cylinder drain cock which will. open automatically when the steam or source of uid pressure is exhausted or shut ed, the provision of an improved cylinder drain coclr which will remain closed with normal cylinder pressure and boiler pressure, the provision of an improved cylinder drain cock providing a continuous connection between the boiler or other source oi? duid pressure (when not otherwise interrupted) and the cylinder, the provision of means for admitting saturated steam to the cylinders a locomotive when it is drifting or runmng with the steam shut off, the provision of means for preventing water of condensation collecting or freezing in the pipes conveying the steam or other power means to the cylinder cocks, the rovision of means for reducing the tenda of the power means by the piston and reducing the consequent cutting action-on the piston and cylinder walls or valve cage, the provision o an improved cylinder relief valve system in which each cylinder cock can operate independently of the others while all of the cocks can be controlled collectively l from the cab of the locomotive by a common power means, the provision of means for placing the cylinder in communication ncy to blowing or sucking with a drain port or the atmosphere whenever the pressure in the cylinder exceeds a predetermined amount under running conditions, the provision of an improved form of cylinder cock which will remain closed against a vacuum in the cylinder, the provision of an improved form of cylinder cock: which will relieve excess pressure without admitting cold air into the cylinder, and generally to improve, simplify and cheapen the construction of cylinder cocks and other` devices for relieving excess pressure and draining liquid from cylinders and other cavities or receptacles subject to iiuid pressure.

In attaining these and other objects and advantages to be hereinafter set forthI have -provided a construction one embodiment of which is illustrated in drawings -in which: Figurel is a diagrammatic view of a loco- 'the accompanying motive with my improved draining and pressure relieving system applied thereto;

Fig. 2 is a vertical section through my improved form of cylinder cock;

Fig. 3 is a section on the line 3 3 of Fi n 2; and

' ig. 4 is a section on theline 4-4 off Fig. 3; V

Fig. 5 is a diagrammatic view showing the connections of the operating line to cylinders on each side of a locomotive.

rihe general arrangement of my improved draining and pressure relieving valve and a system employing the same as applied to Vthe 'cylinders of a locomotive is shown diagrammatically in Fig. l in which the cylinn der cocks 5 are arranged on the under side of the c linder 6. yThese cylinder cocks are under duid pressure control, and in the form herein described are controlled by steam obtained from the boiler by the pipe 7 leading to a three-way cock 8 in the cab under the hand of the engineer.

The cylinder cock itself is shown most clearly in Fig. 2. It comprises a casing 9 having a threaded projection 10 for connection to the cylinder. Within the casing is arranged a, di'erential duplex piston valve device 11 adapted to slide to and fro in the bushing 12 which is threaded into. the casing asf'shown, the lower part 21 of this bushing forming a closing member for the lower part of the casing as well as the valvejseat 13 for the valve portion 14 arranged on the vlower side of the piston 11,

A passage 2O is provided in the part 21 of the bushing for discharging water or other Huid to the atmosphere from the cylinder when the valve portion 14 is raised above its seat.

Steam from the boiler is admitted through the passage 15 into the space 16 above the top of the piston and tends therefore to drive the piston downwardly, but opposing this pressure of the steam in the space 16 is the upward pressure of the spring 17, and also the press-ure on the under side of the 'piston produced by the fluid pressure in the cylinder. Communication between the cylinder and the lower part of this piston is obtained by means of passages 18 arranged in the wall of the casing (see more particularly Figs. 2 and 4).

It will be seen from Fig. 2 that when the valve is closed by the downward pressure of the steam in the space 16, the pressure of the cylinder acts upwardlyon the annular part 19 of the piston 11 whose area is very much less than the area of the top of the piston. Consequently even though the pressure in the cylinder is at times very nearly equal to the pressure in the boiler, the pressure of the steam on top of the piston will be suflicient to hold the valve closed notwithstanding the upward pressure of the steam in the cylinder, and also the upward pressure of the spring 17. l

ln some cases a source of` Huid pressure having a lower pressure than that of the cylinder may be used for holding the valve closed against the cylinder pressure by suitably proportioning the areas of the two sides of the piston and the strength of the spring. Should however, the pressure in the cylinder becomev excessive, owing to accumulation of water, or from any other cause, the pressure of the steam in the space 16 will be overcome with the result that the valve will lift and allow water or other fluid to discharge through the opening 20.

With the construction described when there is no steam pressure accumulated in the boiler or when steam is shut off by the cock 8 the valve in the cylinder cock will open automatically under the laction of the spring, with or without the aid of pressure from the cylinder, which has the advantage that in case the throttle valve of the locomotive leaks the water of condensation can escape freely and further self-starting of the locomotive is avoided @n the other hand the valve in the cylinder cock will open up to drain when the steam or other power means are not exhausted or shut olf so that excessive pressure due to water in the cylinder or other reasons is relieved so that knocking out or failin of cylinder heads andV the production o loose pistons and other defects is avoided.

Furthermore the valve will not open up (power means not being exhausted or shut off) when there is no pressure or a vacuum in the cylinder. This prevents the introduction of cold air into the cylinder when the locomotive is drifting or running with steam shut off, and thus improves the lubrication in the-cylinder by preventing the carbonization of the oil. Y,

Also, as the valve remainsclosed against a vacuum, there is neither pounding of the valve nor consequent distortion thereof and leakage at its seat, such as may occur with valves opening with normal changes in pressure.

A further feature of importance is the provision of means for maintaining a continual connection between the boiler (when not cut off by the cock 8) and the cylinder. This is obtained by means of a restricted passage 22 in the piston which allows a small quantity of steam to leak out of the space 16 into the lower partA of the casing and from thence into the cylinder by means of the passage 18. i

This slight but continuous flow of steam from the boiler to the cylinders serves various important functions. lt prevents water of condensation accumulating and possibly freezing in the pipe 7 leading to the boiler or other source of fluid pressure. Further the admission of saturated steam to the cylinders of the locomotive when it is drifting or running with the steam shut od not on y prevents the formation of a vacuum but also tends toimprove the lubrication.

From the foregoing description it will beY inder 'pressure the pressurek of the steam f from the boiler will overcome the combined Apressure of the steam from the cylinder and the spring and hold the valve closed. When however the pressure in the cylinder rises above a predetermined value, the pressure inthe cylinder aided by the pressure of the spring overcomes the pressure of the steam from the boiler and opens the valve, threbyrelieving the cylinder of excess pressure and any water which may have accumulated,

Having thus described my invention and illustrated its use, what l claim as new and desire to secure by LettersPatent isf .A device of the character described com-I prismg a member having a connection to a cylinder, a connection to a boiler, a drain valve adapted to open when the cylinder pressure rises above a predetermined value and a restricted continuously open connection between said first mentioned connections whereby steam may be admitted to the cylinder from the boiler independently of the cylinder valves proper.

2. A device of the character described comprising a member having a connection to a cylinder, a connection tola boiler, a drain valve adapted to open when the cylinder pressure rises above a predetermined value and a restricted connection between said rst mentioned connections whereby steam may be admitted to the cylinder from the boiler independently of the cylinder valves proper.

3. A device of the character described comprising in combination a casing, a drain port therein, a` piston within said casing, means for communicating boiler pressure to one side of said piston and cylinder pressure to the other side, a valve operated by said piston adapted to interrupt communication between the cylinder and said drain port and a restricted constantly open connection between the two sides of said piston.

4. A device of the character described comprising in combination a casing, a drain port therein, a piston within said casing, means for communicating boiler pressure to one side of said piston and cylinder pressure to the other side, a valve operated by said piston adapted to interrupt communicationbetween the cylinder and said drain port and a restricted connection between the two sides of said piston.

5. A device of the character described comprising, in combination, a casing, a valve within said casing adapted to remain closed under a vacuum, and means for operating said valve, the said valve being provided with means for establishing an independent cognection between the boiler and the cyl- 1n er.

6. A device of the character described com-i prising, in combination, a casing, a valve within said casing adapted to remain closed under a vacuum, and means for operating said valve, the valve being provided with means for establishing a connection between the boiler and the cylinder.-

7. A device of the character described comprising, in combination, a casing, a valve therein arranged to remain closed against a pressure below a predetermined pressure, means for opening and closing the valve, and means for establishing an independent connection between the boiler and the cylinder.

8. A device of the character described comprising, in combination, a casing, a valvel within said casing adapted to remain closed under a pressure below a predetermined pressure, and means for operating said valve, the said valve being provided with means for establishing an independent connection between the boiler and the cylinder.

9. A device of the character described comprising, in combination, a casing, a valve within said casing adapted to remain closed under a pressure below a predetermined pressure, and means for operating said valve, the said valve being provided with means for establishing a connection between the boiler and the cylinder.

In testimony whereof I have hereunto signed my name in the presence of the two subscribing witnesses.

THOMAS W. DEMAREST.

Witnesses:

EDWARD H. Davis, WILLIAM GOLDBERGER. 

